Chembio Diagnostics Inc. reported a wider loss in the January to March period compared with a year earlier because of higher costs for regulatory tests and an expansion into foreign countries.

The Medford-based manufacturer of rapid tests for HIV, syphilis, Ebola and other infectious diseases said it lost $1.6 million in the first quarter that ended March 31. It had lost $303,600 a year earlier.

Sales declined to $6.3 million, a drop of 4.2 percent compared with the same period in 2016.

Still, CEO John Sperzel said Tuesday night that the company was expanding internationally with product sales to Asia, Latin America and Africa.

“We believe the advances made during the first quarter of 2017 demonstrate our commitment to continue building global commercial channels, thereby strengthening our core business in the sexually transmitted disease market, and building a strong position in the high-growth fever and tropical disease market,” he said.

Sperzel also said that by year’s end Chembio would likely fulfill a $5.8 million order from the Brazilian government for HIV tests and test components.

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A separate combination test for HIV and syphilis cleared several regulatory hurdles in the first quarter.

The test received a CE mark, which allows Chembio to begin selling it in Europe and most of the Caribbean.

A clinical trial of the HIV/syphilis test in the United States was completed after about a year’s work. But Sperzel said the U.S. Food and Drug Administration “has requested further clinical studies in addition to those recently completed.”

The company also has begun selling a test for Zika and a combination test for Zika, Dengue and Chikungunya diseases to the U.S. Centers for Disease Control and Prevention for use in a pilot testing program in Peru, India, Guatemala and Haiti.

The earnings announcement came after the stock market closed Tuesday. Chembio shares closed up 30 cents, or 4.5 percent, to $6.95 on Wednesday on the Nasdaq Stock Market.